Update thirdparty.md

add Wechat-oauth2-client

Author: oakhope

docs/providers/thirdparty.md

@@ -85,6 +85,7 @@ Gateway | Composer Package | Maintainer
 [Vend](https://github.com/wheniwork/oauth2-vend) | wheniwork/oauth2-vend | [When I Work](https://github.com/wheniwork)
 [Vimeo](https://github.com/saf33r/oauth2-vimeo) | saf33r/oauth2-vimeo | [Safeer Ahmed](https://github.com/saf33r)
 [Vkontakte](https://github.com/j4k/oauth2-vkontakte) | j4k/oauth2-vkontakte | [Jack W](https://github.com/j4k)
+[Wechat](https://github.com/oakhope/oauth2-wechat) | oakhope/oauth2-wechat | [Benji Wang](https://github.com/oakhope)
 [Wrike](https://github.com/michaelKaefer/oauth2-wrike) | michaelkaefer/oauth2-wrike | [Michael Käfer](https://github.com/michaelKaefer)
 [Yahoo](https://packagist.org/packages/hayageek/oauth2-yahoo) | hayageek/oauth2-yahoo | [Ravishanker Kusuma](https://github.com/hayageek)
 [Yandex](https://packagist.org/packages/aego/oauth2-yandex) | aego/oauth2-yandex | [Alexey](https://github.com/rakeev)